Watch the official second trailer for Rogue One: A Star Wars Story, in which Jyn Erso leads a group of unlikely heroes to steal the plans to the Death Star, the Empire’s ultimate weapon of destruction.

The second trailer shows more back story to Jyn Erso’s character, plus we find out that Forest Whitaker’s character has robotic legs. It’s the first major film set outside of the traditional saga, and has been characterized as “an experiment” by the company’s CEO, Bob Iger.

In that first Star Wars movie Princess Leia, played by Carrie Fisher, announces a lot of people died to get the blue prints. Rogue One: A Star Wars Story is about the crew assembled that stole the blue prints for the Deathstar, which Luke Skywalker eventually blew up in the 1977 film.

Rogue One: A Star Wars Story arrives in theaters December 16, 2016.

From Lucasfilm comes the first of the Star Wars standalone films, Rogue One: A Star Wars Story, an all-new epic adventure. In a time of conflict, a group of unlikely heroes band together on a mission to steal the plans to the Death Star, the Empire’s ultimate weapon of destruction. This key event in the Star Wars timeline brings together ordinary people who choose to do extraordinary things, and in doing so, become part of something greater than themselves.